Gear You'll Use in Your Course, Piece by Piece

Your first scuba course puts a lot of unfamiliar equipment in front of you, and most of it does a job you have never had to think about. This guide walks through the kit you will use on an Open Water course in Australia: what the school normally supplies, what each piece does, and what your instructor will show you in the pool.

You do not need to own any of it to start. The bulky, technical items are part of the course, and by the end you will have put them together and taken them apart many times.

What the school supplies, and what you might bring

What is included varies from school to school, so ask before you book. PADI's own course page says most dive shops expect students to bring their own mask, snorkel and fins, and that the regulator, buoyancy control device (BCD), dive computer and cylinder may or may not be included in the training price. You may also need to rent a wetsuit.

Australian schools show the range. Dive Centre Manly includes all dive gear in its Open Water course, mask, snorkel and fins included. Frog Dive includes gear hire and gives students a free pair of boots, but for hygiene reasons it does not hire out masks, snorkels or boots, so students buy a mask and snorkel set (from $65 in its shop). Divers Den in Cairns includes all dive and snorkel equipment in its four-day Open Water course.

Queensland's code of practice for recreational diving gives a handy checklist of what a diver in training should wear: a mask, fins, a scuba cylinder, a BCD with a power inflator, a regulator with an alternate air source, depth and cylinder pressure gauges, a quick-release weight system and exposure protection to suit the conditions, plus a snorkel and a timing device for entry-level students. Each piece is explained below.

Thinking of buying your own?

What to buy, what to keep hiring and in which order is covered in our guide to what scuba gear to buy first. Read it before you spend anything, because everything in this article can be hired while you learn.

The scuba unit: cylinder, regulator and BCD

These three pieces connect into what instructors call the scuba unit, and assembling it is one of the first things you learn.

The cylinder, or tank, holds air at high pressure. Scuba cylinders have working pressures of roughly 184 to 300 bar, and 232 bar is one of the most common ratings. In Australia a cylinder must pass visual, hydrostatic and other tests every 12 months, and a fill station should not fill one without a valid test date, so the school's tanks arrive tested and filled. You will learn to open the valve and read the pressure.

The regulator turns that high-pressure air into air you can breathe. Its first stage fixes to the cylinder valve, with either a yoke clamp or a screw-in DIN fitting, and drops the pressure to an intermediate level, usually about 8 to 11 bar above the surrounding water. Hoses run from the first stage to:

- the second stage, the mouthpiece you breathe from, which gives air only when you inhale; - a spare second stage, called the octopus or alternate air source, for a buddy who runs short of air; - the submersible pressure gauge (SPG), or a computer reading the same port, which shows how much air is left; - the low-pressure inflator hose that feeds your BCD.

Our article Scuba Dive Regulators Explained goes into more detail.

The BCD (buoyancy control device, or BC) is the jacket or harness that holds the cylinder on your back and lets you control your buoyancy. Air goes into its bladder through the inflator hose, or by blowing into the oral inflation valve, and comes out through the deflator and dump valves. You add air to float at the surface and small amounts at depth to hover, and let it out to go down. Many BCDs have weight pockets built in.

Mask, snorkel, fins and boots

The mask. Your eyes cannot focus properly when water touches them. A mask puts a pocket of air in front of your eyes so they can focus nearly normally, and it covers your nose so you can breathe a little air into it to equalise the mask as you descend. Dive masks use tempered glass and a soft silicone or rubber skirt that seals against your face.

The snorkel lets you breathe at the surface with your face in the water, so you can swim out to a site without using tank air. Queensland's code lists one for entry-level students. Masks with a built-in snorkel are for surface snorkelling only and are not used for scuba.

Fins. Most diving fins are open-heel: the foot pocket is open at the back and an adjustable strap or spring holds the fin on, worn over a neoprene boot. Full-foot fins are worn on bare feet. Open-heel fins are the usual choice where divers walk into the water from the shore and need their feet protected.

Boots are that protection, and many hire fins need them: Frog Dive's hire fins, for example, are open-heel models that must be worn with boots.

Wetsuit and weights

The wetsuit keeps you warm mainly through the tiny gas bubbles trapped in its neoprene foam. The layer of water between suit and skin is often credited with the warmth, but it adds little; the gas in the foam does the insulating. The same bubbles make the suit float, which is one reason you need weights, and they squash as you go deeper: at about 15 metres a typical neoprene foam is half its surface thickness and loses heat about three times as fast. Which thickness suits which water is covered in Wetsuit Thickness for Australian Waters.

Weights. Your body, your wetsuit and an aluminium cylinder all tend to float, so divers carry lead on a weight belt or in BCD pockets to counter it. The weights need a quick release, so that you or your buddy can drop them in an emergency. Our beginner's guide to diving weights explains how much you might need.

The dive computer, or gauges

A dive computer measures your depth and time underwater and uses them to show how long you can stay before you would need decompression stops, your no-decompression limit. It also records each dive. PADI lists a dive computer among the basic gear for its Open Water course, but schools differ in what they lend. Whatever you are given, you need a way to see your depth, your time and your remaining air: Queensland's code lists depth and pressure gauges and a timing device for students.

What you will be shown in the pool

The first pool session usually starts with the gear rather than the water. Expect your instructor to show you how to:

- Assemble the scuba unit. Strap the cylinder into the BCD, fit the regulator first stage to the valve, connect the inflator hose, then open the valve and check that everything works. Every training agency expects certified divers to be able to assemble and test their own set. - Check you are breathing from a full, open cylinder. Breathe from both second stages before you get in and watch the pressure gauge as you do: if the needle swings with each breath, the valve may not be fully open. DAN also warns that a gauge can read full from air left in the hoses after the valve has been shut. - Do a buddy check. Many instructors use the letters BWRAF: BCD, Weights, Releases, Air and Final check, so that you know how your buddy's inflator, weights and buckles work as well as your own. - Use the BCD. Add and dump air with the inflator buttons, and inflate it by mouth. - Handle the regulator and mask underwater. Clear water from your mask and from a regulator second stage, recover a regulator that has come out of your mouth, and breathe from a buddy's octopus. Our article on what to expect in your pool sessions covers each skill. - Pack up. Close the cylinder valve and purge the regulator to release the pressure in the hoses before taking it off.

Looking after hire gear

Hire gear is fine to learn on, but check it like your own. DAN advises inspecting any rental equipment carefully before you dive. Tell your instructor straight away if a regulator is hard to breathe from or starts to free-flow, or if the BCD inflator leaks: DAN lists all three among the equipment problems that use up a diver's air. Rinse everything in fresh water after the session, and see our tips on looking after a BCD.

Next in your course come the open water training dives, where the same gear and skills move into the sea.

Sources

- PADI: Open Water Diver course (Australia) - Dive Centre Manly: PADI Open Water Course - Frog Dive: PADI Open Water Diver Course - Frog Dive: Gear Hire - Divers Den: Four Day PADI Open Water Course - Queensland Government: Recreational Diving, Recreational Technical Diving and Snorkelling Code of Practice 2018 (section 3, equipment for resort and entry-level divers), worksafe.qld.gov.au - WorkSafe Victoria: Explosion during the filling of scuba cylinders - DAN: The Importance of a Predive Safety Check - DAN: The Most Common Causes of Out-of-Air Emergencies - DAN: Safety Tips to Prevent Out of Air Emergencies - Wikipedia: Diving cylinder - Wikipedia: Diving regulator - Wikipedia: Buoyancy compensator (diving) - Wikipedia: Diving mask - Wikipedia: Snorkel (swimming) - Wikipedia: Swimfin - Wikipedia: Wetsuit - Wikipedia: Diving weighting system - Wikipedia: Dive computer - Wikipedia: Scuba skills

Header photo: A diver in full scuba kit, with regulator, octopus and BCD, during a pool session in Maidstone, by Tim Sheerman-Chase, CC BY 2.0, via Wikimedia Commons.